1. Field of the Invention
The present invention relates to a technique for managing encrypted data on a write-once recording medium.
2. Description of the Related Art
Conventional write-once recording media, also referred to as write once read many (WORM) media, are known to prevent written data from being physically changed or erased.
Generally, to reliably erase data written to a WORM medium, it is necessary to physically destroy the recording medium itself. Another conventional technique related to WORM media is known to change data not physically but logically. This technique has a specific rule. For example, an alternative area is provided for a storage area having written data in the WORM medium, and the alternative area is preferentially read as the original storage area.
write-once recording media are not provided with a function of physically erasing data. Therefore, conventionally, to safely erase data written to a write-once recording medium, i.e., to acquire a state where reading and analyzing data are very difficult, the medium itself has to be destroyed.